


I Am Not You

by QuietBreeze



Category: Undertale (Video Game)
Genre: Alternate Self, Alternate Universes, Family, Father-Son Relationship, Gen, Good and Evil, Morality, Morally Ambiguous Character, Multiple Personalities, Multiple Timelines, Multiverse, Self Torment
Language: English
Status: Completed
Published: 2016-12-08
Updated: 2016-12-08
Packaged: 2019-03-05 05:54:40
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,382
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13381551
Author URL: https://archiveofourown.org/users/QuietBreeze/pseuds/QuietBreeze
Summary: There are millions of alternate universes out there, and with them come alternate personalities. Gaster is no different, and he might be ashamed of the result.





	I Am Not You

In one world, he is a villain; an instrument of torture, getting revenge on the ones who trapped him in a ceaseless void of nothingness.

But in another world, he is a good creature. He has family he cares about, and a promise to keep. He is held to that vow, and even in his state, he will always stick to it. He is  _determined_  to.

Sometimes, however, worlds collide. Parallel universes meet at an angle. What will happen then? Which side will overrule the other? And what personality will Wingdings Gaster cling to?

_This is when you discover who you really are._

* * *

There was a beautiful soul within his grasp – one belonging to a monster he knew very well. It felt wonderful to have it between his fingers again, to study and make his own. The familiar face looked up at him in anger, pretending that the tears in the corners of his sockets weren't there. He reached out his hand, trying to conjure up magic, but alas, it would not come.

Gaster smiled triumphantly. Of course it wouldn't come. He had taken his soul; his son had lost everything, and was now vulnerable.

He clenched his fist, and the soul began to crack. There was a cry of pain, eliciting another smile from the failed scientist. What power he suddenly had over him. Yes, he had been the weak one at first – Sans was powerful after all – but now it was Gaster who held dominance. It felt insanely good. He had no power at all in the void, but all it took was a small step into the real world again, and he suddenly had everything.

" _You didn't think it would happen, did you?"_

He was speaking now, his language, that of the Wingdings, being indecipherable to most. But this boy understood it, as he had always done, and the words made him cower.

" _You didn't think I would get my powers back. You're not as wily as you think, Sans. Now you're going to pay the price. You're going to live up to the purpose you were created for."_

But just as he was about to use his newfound strength to crush the fragile soul entirely, he stopped. A voice had sounded in his head, and it was more than just a thought. It felt so… real.

_Stop this. What do you think you're doing?_

It was so familiar, in a way he couldn't put his finger on. It was far away, and yet right there with him. It reminded him of a voice he knew like the back of his hand. Why wouldn't a name come to him?

 _This isn't you. This isn't us._ it asserted.  _He's your son. We love him. I love him._

_It's me._

That was his voice, undoubtedly. But it wasn't just a thought process, nor a second personality. This was a totally separate voice, finding its way into his brain. But where was it from? How could there be another  _him_?

But as soon as he asked himself the question, the answer came to him immediately. His experience of the void made him very aware of other universes, other timelines with a million possibilities. Of course there would be other versions of him – of  _everyone_  – out there. But how could they connect? How could he hear himself so easily, all of a sudden? And why  _now_?

Regardless, the influence of his own was felt, deep within his soul. As he held the quivering heart between his fingertips, his gaze shifted between it and the weak skeleton on his knees before him. Was the pain of his son suddenly hurting him too? For some reason, it had come like a bullet, making him experience feelings he never knew existed. Regret. Guilt. Shame.

Love.

" _No. get out of my head, you filthy creature. You aren't me."_

_Yes, I am. You know I am, so you're going to listen to me. I can already feel you wavering._

" _I am NOT wavering. I feel nothing except anger, and no-one will change that. Do you even know the life I have led?"_

_Every part of it. From our normal life, all the way to the immortality in the void. I know the pain you're feeling. It's completely taken me over. But don't let it make you into a cruel beast. You become stronger by resisting those temptations, not embracing them._

He was actually pausing to think about it. When had he ever done that? Never. And he actually looked at his son with some feeling of… remorse? It was an alien sensation, but it felt so right at the same time.

" _But he deserves to die."_

_He absolutely does not._

" _I made my choice."_

_That is your son in front of you. You're really just going to murder him?_

" _Leave me."_

_What kind of monster are you?_

With a frustrated yell, Gaster released his grip on the fragile soul, letting it fly away from him and straight back into the chest of the vulnerable skeleton, who was clutching the floor for dear life. Then, as soon as the soul was in him again, he perked up, all signs of injury or weakness draining away. He looked up in dismay, the round sockets meeting Gaster's shocked stare.

"Change of h-heart, h-huh?" Sans stammered, though not without a bitter tone.

Gaster sighed, still at a loss himself.  _"Perhaps,"_ he muttered.  _"But you should just leave now."_

"What if I don't want to? What if I n-need answers?"

" _Just get out if you know what's good for you."_

So he hadn't gone completely soft, at least.

He turned his back, as if to pretend his son wasn't there, refusing to speak until he was sure he'd left. There was a steadfastness in that boy though – a  _determination_ to get to the bottom of any questions he harboured. He wouldn't answer him though, no matter how much he pressed him. The presence lingered for a long time, the two of them waiting to see if either would make a move. No-one did.

And then, finally, Gaster felt a shuffling of feet.

He turned around, and Sans was gone.

* * *

"There is another me. In another universe."

The child sat beside Gaster, leg crossed and chin up as they stared at him and listened to his story intently.

"I met him today. He wasn't like me though; he was a cruel creature, so I thought I would try and help him see that. You understand why I did what I did, don't you?"

He looked to the human for a response, and smiled when they gave him an elaborate, excitable nod. Their company was certainly infectious, and he could only be grateful for the way the two could communicate like this, despite his usual confinement to his virtual cell. When they met, Gaster talked. And when he talked, Frisk listened.

"Well, I'm sadly unable to see into that universe to make sure," he admitted, stroking the back of his skeletal head. "It took enough power to get through once, and it would be too difficult to try it again. But… I at least feel as if I achieved something."

Silence for a moment, allowing Gaster to gather his thoughts. No doubt he would be pondering his experience for a long time, so he would use up some of that time now. After a moment or two, there was a gentle hand on his. He met Frisk's shiny eyes as they stared up at him, the smile still on her face, eliciting a smile from himself. How they kept being so cheerful, he had no idea. This was probably their third or fourth time journeying the Underground. He wondered if they were tired. After all, he certainly was.

He gripped their small fingers, as if trying to keep them with him for as long as possible. He felt like he needed the comfort, as the thoughts of the evil he'd witnessed kept crawling into his head. Maybe he'd see this evil again – perhaps totally changed. Or perhaps not. He could only hope he'd made a difference.

 _For his sake_ , he thought, as his nightmarish thoughts were quickly replaced by an image of his smiling son. He relaxed a little. That was something worth fighting for.

 

**Author's Note:**

> Thank you for reading! So for some reason I decided to write about Gaster again. He's not even one of my favourite characters, but I find the mystery around him so fascinating, so I guess that's why I feel the need to write about him.
> 
> This is pretty much inspired by people's different interpretations of Gaster: some people see him as a villain, while others see him as a caring father to his sons. So I decided to merge the two ideas together.
> 
> I enjoyed writing this, so I hope you enjoyed reading! Please leave reviews!


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